WO2019124390A1

WO2019124390A1 - Crane

Info

Publication number: WO2019124390A1
Application number: PCT/JP2018/046610
Authority: WO
Inventors: 尚隆増田; 健二漆原; 貴史川野
Original assignee: 株式会社タダノ
Priority date: 2017-12-18
Filing date: 2018-12-18
Publication date: 2019-06-27
Also published as: CN111465573A; US20200377346A1; EP3730446A1; JP6593571B1; CN111465573B; US10836612B1; EP3730446A4; JPWO2019124390A1

Abstract

The present invention is provided with: a manipulation unit; a winch device that operates with an actuation mode of either a high speed mode or a low speed mode on the basis of manipulation of the manipulation unit, and winds in or reels out a wire rope to which a hook is fixed; a selection unit for an operator to select either the high speed mode or the low speed mode; a load calculation unit for calculating a suspended load; a tension calculation unit for calculating the tension of the wire rope; and a control unit for controlling the actuation of the winch device. If the mode selected by the selection unit is the high speed mode and the manipulation unit is manipulated from a neutral state to a non-neutral state, and the suspended load is smaller than a load threshold and the tension is smaller than a tension threshold, the control unit controls the winch device so as to operate in the high speed mode. Through this, a winch system of a mobile crane having excellent operability is provided.

Description

crane

The present invention relates to a crane. In particular, the present invention relates to a crane comprising a winch system for controlling the displacement of a high and low speed hydraulic motor with a detected load.

A wide range of tensions and speeds are required for wire ropes driven by the hydraulic winches of mobile cranes. As one of the means to achieve that, a variable displacement motor is used.

There is also a technique called free fall for freely lowering the hook provided at the end of the wire rope. In order to realize this technology, a clutch is provided between the fixed displacement motor and the winch drum. Then, when realizing the free fall, the operator frees the hook provided at the tip of the wire rope by disconnecting the clutch. Instead of such a free fall, a variable displacement motor is also used to realize a high speed lowering of the wire rope.

Mobile cranes have load detectors for lifting loads. A technology has been developed to control the displacement of a variable displacement motor based on the load detected by the load detector. One type of variable displacement motor is a high and low speed hydraulic motor that can be switched to either a large displacement or a small displacement.

In the case of the winch system described in Patent Document 1, the lifting load calculated immediately before the start of the lowering operation by the overload prevention device is stored as an effective lifting load until the end of the lowering operation. Then, when the actual action lifting load is smaller than a predetermined value, the operation mode of the winch system is switched to the high speed mode.

Patent No. 4527860

The winch system described in Patent Document 1 is a technique for lowering a suspended load in a suspended state. Therefore, it can not be applied to the winding operation from the ground cutting where the lifting load detected by the overload prevention device immediately before the start of the winch operation becomes zero. Therefore, in the case of the invention described in Patent Document 1, there is a problem that the workability at the time of ground cutting can not be improved.

An object of the present invention is to realize a crane capable of improving the workability.

One aspect of the crane according to the present invention operates in either the high speed mode or the low speed mode based on the operation of the operation unit and the operation unit, and performs winding and unwinding of the wire rope to which the hook is fixed. The operation of the winch device, the selection unit for the operator to select between the high speed mode and the low speed mode, the load calculation unit for calculating the suspension load, the tension calculation unit for calculating the tension of the wire rope, and the winch device The control unit controls the control unit such that the mode selected by the selection unit is the high-speed mode, the operation unit is operated from the neutral state to the non-neutral state, and the suspension load is higher than the load threshold And control the winch device to operate in the high speed mode if the tension is less than the tension threshold.

ADVANTAGE OF THE INVENTION According to this invention, the crane which can improve workability | operativity is realizable.

It is a figure showing a rough terrain crane concerning an embodiment of the present invention. It is a figure showing a winch system. It is a block diagram of a controller. It is a flowchart showing the process performed by a controller. It is a flowchart showing the process performed by a controller. It is a flowchart showing the process performed by a controller. It is a figure which shows the rough terrain crane of the state which is lifting the suspended load.

FIG. 1 shows a rough terrain crane 2 according to an embodiment of the present invention. The rough terrain crane 2 has a winch system 1. The rough terrain crane 2 has the turning unit 4 rotatably mounted on the vehicle unit 3. The vehicle unit 3 is provided with an outrigger 5. The rough terrain crane 2 shown in FIG. 1 has an outrigger 5 overhanged.

A driver's cab 7 is mounted on the turning frame 6 of the turning unit 4. An operating lever 10 of the winch system 1 is disposed in the operator's cab 7. A winch 11 is disposed on the turning frame 6. The telescopic boom 12 is pivotably attached to the pivoting frame 6. A relief cylinder 13 is disposed between the telescopic boom 12 and the turning frame 6. The rough terrain crane 2 shown in FIG. 1 is a crane working posture in which the telescopic boom 12 is extended after the telescopic boom 12 is raised and lowered by the relief cylinder 13.

As shown in FIG. 1, the wire rope 14 fed from the winch 11 is wound around between the tip 15 of the telescopic boom and the hook 16. A hook wire rope 14 is hung on the hook 16 to suspend the load 18. The rough terrain crane 2 shown in FIG. 1 is in a state immediately before ground cutting where the suspended load 18 is grounded to the ground 20.

FIG. 2 is a hydraulic circuit and control block diagram constituting the winch system 1 of the rough terrain crane 2 according to the embodiment of the present invention. The winch 11 has a high and low speed hydraulic motor 21 capable of driving the winch drum 22 forward and reversely via the reduction gear 23. The high and low speed hydraulic motor 21 can switch the rotation speed with respect to the supply flow rate to one of the high speed mode and the low speed mode by switching the capacity required for one rotation. When the high and low speed hydraulic motor 21 is in the high speed mode, the operation mode of the winch 11 is the high speed mode. On the other hand, when the high and low speed hydraulic motor 21 is in the low speed mode, the operation mode of the winch 11 is the low speed mode. The motor capacity of the high and low speed hydraulic motor 21 is always biased to the large capacity side. The motor displacement is controlled by the control cylinder 24.

A high speed / low speed hydraulic motor 21 is connected to a winding-side oil passage 25 and a winding-side oil passage 26. A counter balance valve 27 is interposed in the oil passage 25 on the winding side. A shuttle valve 28 is interposed between the oil passage 25 on the winding side and the oil passage 26 on the lowering side. The shuttle valve 28 and the control cylinder 24 are connected by an oil passage 31 via a pilot switching valve 30. The shuttle valve 28 picks up the motor operating pressure generated in the oil passage 25 on the winding side or the oil passage 26 on the lowering side, and transmits it to the pilot switching valve 30. The pilot switching valve 30 switches the motor operating pressure to and from the control cylinder 24.

The pilot switching valve 30 is in communication with the solenoid switching valve 33 via an oil passage 34. When the pilot pressure is sent from the electromagnetic switching valve 33 to the pilot switching valve 30 via the oil passage 34, the pilot switching valve 30 is switched to the communication side. The pilot switching valve 30 and the solenoid switching valve 33 constitute a high / low speed switching valve. When the motor operating pressure is communicated from the pilot switching valve 30 to the control cylinder 24 (when hydraulic fluid is supplied), the high / low speed hydraulic motor 21 is switched to the small displacement side corresponding to the high speed side. On the other hand, when the supply of hydraulic fluid from the pilot switching valve 30 to the control cylinder 24 is shut off, the high and low speed hydraulic motor 21 is switched to the large capacity side corresponding to the low speed side.

An oil passage 25 on the winding side and an oil passage 26 on the lowering side are in communication with a pilot switching valve 32 that controls the direction and flow rate of pressure oil supplied to the winch 11. The pilot switching valve 32 is in communication with the solenoid proportional valve 35 on the winding side by an oil passage 37. The pilot switching valve 32 is in communication with the solenoid proportional valve 36 on the lower side by an oil passage 38. The pilot switching valve 32 and the hydraulic pump 40 are connected by an oil passage 42 on the pump side. The pilot switching valve 32 and the oil tank 41 are communicated by an oil passage 43 on the return side. The pilot switching valve 32 is controlled in switching direction and switching amount by the solenoid proportional valve 35 and the solenoid proportional valve 36.

As shown in FIG. 2, the controller 50 is in signal communication with the control lever 10, the speed mode selection means 51, the load detection means 52, and the wire rope hook number input means 53, respectively. Specifically, the load detection means 52 is composed of a boom length detector 54, a boom angle detector 55, and a relief cylinder pressure detector 56 which are respectively known. The controller 50 is also in signal communication with the high / low speed switching electromagnetic switching valve 33, the winding-side electromagnetic proportional valve 35, and the lowering-side electromagnetic proportional valve 36, respectively.

The control lever 10 is disposed in the driver's cab (see FIG. 1), and is energized to either the winding-side solenoid proportional valve 35 or the winding-side solenoid proportional valve 36 according to the switching direction of the control lever 10 Is selected. Furthermore, the level of the strength of the signal sent to the

proportional solenoid valves

35, 36 changes in accordance with the amount of operation of the control lever 10. The operation lever 10 corresponds to an example of the operation unit.

The speed mode selection means 51 is disposed in the driver's cab (see FIG. 1). The operator in the driver's cab can select either the high speed side or the low speed side by the speed mode selection means 51. The speed mode selection unit 51 corresponds to an example of a selection unit.

The wire rope hook number input means 53 is disposed in the driver's cab (see FIG. 1). The operator in the driver's cab can manually input the recognized multiplication number from the wire rope multiplication number input means 53. The wire rope hook number input means 53 may be arranged such that the wire rope hook number detector is disposed at the distal end portion 15 (see FIG. 1) of the telescopic boom to automatically input the wire rope hook number.

FIG. 3 is a block diagram of the controller 50. As shown in FIG. The controller 50 includes a suspension load calculation unit 60, a wire rope tension calculation unit 61, a suspension load comparison unit 62, a wire rope tension comparison unit 63, and a drive control unit 64.

As an example, the suspension load calculation unit 60 is suspended from the boom length detected by the boom length detector 54, the boom angle detected by the boom angle detector 55, and the relief cylinder pressure detected by the relief cylinder pressure detector 56. Calculate the load. The suspension load calculation unit 60 corresponds to an example of a load calculation unit.

The wire rope tension calculation unit 61 calculates the wire rope tension from the suspension load calculated by the suspension load calculation unit 60 and the number of wire rope hooks input by the wire rope hook number input unit 53, as an example. The wire rope tension calculating unit 61 corresponds to an example of a tension calculating unit.

The suspension load comparison unit 62 compares the suspension load calculation value calculated by the suspension load calculation unit 60 with one suspension load threshold value stored in the suspension load comparison unit 62. The suspension load threshold is a value larger than a wire rope tension threshold described later. The wire rope tension comparison unit 63 compares the wire rope tension calculation value calculated by the wire rope tension calculation unit 61 with one wire rope tension threshold value stored in the wire rope tension comparison unit 63. The wire rope tension threshold may be set in consideration of the allowable pressure of the high and low speed hydraulic motor 21 whose motor displacement is switched to a small displacement, the specification of the winch system 1, and the like.

The drive control unit 64 outputs a switching signal of the electromagnetic switching valve 33 based on the signals from the control lever 10, the speed mode selection unit 51, the suspension load comparison unit 62, and the wire rope tension comparison unit 63, as an example. Specifically, in the drive control unit 64, the speed mode selection means 51 is selected to the high speed side (condition 1), the control lever 10 is operated from neutral to non-neutral (condition 2), and the suspension load calculation value is the suspension load When all the four conditions of smaller than the threshold (condition 3) and the calculated wire rope tension value smaller than the wire rope tension threshold (condition 4) are satisfied, a signal for switching the electromagnetic switching valve 33 to the high speed side Output.

In other words, in the drive control unit 64, the operation mode selected by the speed mode selection unit 51 is the high speed mode (high speed side), and the operation lever 10 is operated from the neutral state to the non-neutral state. The winch 11 is controlled to operate in the high speed mode when the suspension load calculation value is smaller than the suspension load threshold and the wire rope tension is smaller than the wire rope tension threshold. That is, in the case of the present embodiment, even when the operator selects the high speed side by the speed mode selection means 51, the winch 11 does not operate in the high speed mode if the above conditions 2 to 4 are not satisfied. The drive control unit 64 corresponds to an example of the control unit.

The operation of the winch system 1 of the rough terrain crane 2 according to the embodiment described above will be described. FIG. 4 is a flowchart showing the process performed by the controller 50.

(In case of ground winding by high speed mode selection)
An example of control in the case of winding up in high speed mode from the state (refer FIG. 1) in which the suspended load 18 earth | grounded on the ground 20 is demonstrated. As shown in FIG. 4, in step S1, the controller 50 determines whether the mode selected by the speed mode selection unit 51 is the high speed side (high speed mode). In step S1, when the speed mode selection means 51 is selected to the high speed side ("YES" in step S1), the control processing shifts to step S2. On the other hand, when the mode selected by the speed mode selection means 51 is not the high speed side (high speed mode) in step S1 ("NO" in step S1), the control processing shifts to step S15. In the case of this example, the controller 50 determines YES in step S1.

Next, in step S2 of FIG. 4, the controller 50 determines whether the control lever 10 is neutral (also referred to as a neutral state). In step S2, when the control lever 10 is neutral ("YES" in step S2), the control process proceeds to step S1. When the operation lever 10 is not neutral in step S2 ("NO" in step S2), the control process shifts to step S3. The case where the control lever 10 is not neutral means, for example, a state where the control lever 10 is operated from the neutral state to the non-neutral state. The non-neutral state includes a state in which the control lever 10 is positioned on the winding side and a state in which the operating lever 10 is positioned on the unwinding side. By repeating steps S1 and S2, controller 50 determines whether or not operation lever 10 has been switched from the neutral state to the non-neutral state in a state where operation mode selection means 51 is selected to the high speed side. Do. In the case of this example, the controller 50 determines NO in step S2.

As one example, when the operation lever 10 is operated from neutral to the winding side in step S2 of FIG. 4, the controller 50 outputs a drive signal to the solenoid proportional valve 35 on the winding side in step S3 of FIG. Then, the pilot pressure acts from the solenoid proportional valve 35 shown in FIG. 2 via the oil passage 37, and the pilot switching valve 32 is switched to the winding side. As a result, pressure oil is sent from the hydraulic pump 40 via the oil passage 42 to the oil passage 25 on the winding side. Thus, the working pressure of the high and low speed hydraulic motor 21 is established in the oil path 25 on the winding side.

Next, in step S4 of FIG. 4, the controller 50 determines whether the suspension load calculation value is smaller than the suspension load threshold. As an example, since the wire rope 14 stretches and the telescopic boom 12 sags at the initial ground cutting, the suspension load calculation value is very small. Therefore, in the case of this example, the controller 50 determines YES in step S4. The suspension load threshold may be, for example, a threshold for detecting a ground cutting operation. In this case, in step S4 of FIG. 4, the controller 50 determines whether or not the ground cutting operation is being performed by comparing the suspension load calculation value with the suspension load threshold value.

Next, in step S5 of FIG. 4, the controller 50 determines whether the calculated wire rope tension value is smaller than the wire rope tension threshold value. As an example, at the initial stage of ground cutting, the wire rope tension calculation value is very small because the extension of the wire rope 14 and the deflection of the telescopic boom 12 occur. Therefore, in the case of the groundbreaking initial stage, the controller 50 determines YES in step S5. At this point, the speed mode selection means 51 is selected to the high speed side (condition 1), the operation lever 10 is operated from neutral to non-neutral (condition 2), and the suspension load calculated value is smaller than the suspension load threshold (condition 3) And the wire rope tension calculation value is smaller than the wire rope tension threshold (condition 4). It is determined that all the four conditions are satisfied. The wire rope tension threshold may be, for example, a threshold for detecting a ground cutting operation. In this case, in step S5 of FIG. 4, the controller 50 determines whether the ground cutting operation is being performed by comparing the calculated wire rope tension value with the wire rope tension threshold value.

Next, in step S6 of FIG. 4, the controller 50 controls the drive control unit 64 to output the high-speed side switching signal to the electromagnetic switching valve 33. As shown in FIG. 2, the electromagnetic switching valve 33 is switched to the communication side, the pilot pressure acts on the pilot switching valve 30 via the oil passage 34, and the pilot switching valve 30 is switched to the communication side. Then, the motor operating pressure generated in the oil passage 25 on the winding side acts on the control cylinder 24 via the shuttle valve 28, the pilot switching valve 30, and the oil passage 31. As a result, the control cylinder 24 switches the high and low speed hydraulic motor 21 to the high speed side. Then, the control process transitions to step S7 shown in FIG.

As described above, if the high speed mode is selected by the speed mode selection means 51, the hoisting start is started at high speed at the ground cutting initial stage where the calculated lifting load value and the calculated wire rope tension value are small regardless of the actual lifting load. Do.

Next, in step S7 of FIG. 5, the controller 50 determines whether or not the suspension load calculation value is not smaller than the suspension load threshold value for a predetermined time. In step S7, if the state in which the suspended load calculation value is not smaller than the suspension load threshold (the suspended load calculation value is greater than or equal to the suspension load threshold) continues for a predetermined time ("YES" in step S7), the control process And transition to step S11 of FIG. On the other hand, in step S7, when the suspension load calculation value is not smaller than the suspension load threshold (the suspension load calculation value is not less than the suspension load threshold) is not continuous for a predetermined time ("NO" in step S7), control The processing shifts to step S8 in FIG.

As an example, several seconds are set as the predetermined time. Since the condition is to continue for several seconds, it is possible to prevent the control from becoming unstable due to the apparent load fluctuation accompanying the vibration of the telescopic boom or the wire rope. At the initial stage of ground cutting, the suspended load calculation value is very small. Therefore, in the case of the groundbreaking initial stage, the controller 50 determines NO in step S7. In addition, when vibration occurs in the telescopic boom or the wire rope, the predetermined time takes into consideration the time required for the load fluctuation to be settled after the apparent load fluctuation occurs due to the vibration. It may be determined.

Next, in step S8 of FIG. 5, the controller 50 continues the predetermined time in a state where the calculated wire rope tension value is not smaller than the wire rope tension threshold (the calculated wire rope tension value is equal to or greater than the wire rope tension threshold) Decide whether or not. In step S8, when the wire rope tension calculated value is not smaller than the wire rope tension threshold (the wire rope tension calculated value is equal to or greater than the wire rope tension threshold) continues for a predetermined time ("YES" in step S8) The control process proceeds to step S11 in FIG. On the other hand, if the wire rope tension calculated value is not smaller than the wire rope tension threshold in step S8 (the wire rope tension calculated value is equal to or greater than the wire rope tension threshold) does not continue for a predetermined time (NO in step S8). "", The control process proceeds to step S9 in FIG.

As an example, as in step S7, several seconds are set as the predetermined time. Here too, at the initial stage of ground cutting, the calculated wire rope tension value is very small, so it is judged as NO. In the above-mentioned predetermined time, for example, when vibration occurs in the telescopic boom or the wire rope, the time required for the wire rope tension fluctuation to be settled after the apparent wire rope tension fluctuation occurs due to the vibration It may be determined in consideration of

Next, in step S9 of FIG. 5, the controller 50 determines whether the speed mode selection means 51 is selected to the low speed side. In step S9, when the speed mode selection means 51 is selected to the low speed side, the control process proceeds to step S11 of FIG. On the other hand, when the speed mode selection means 51 is not selected to the low speed side in step S9, the control processing shifts to step S10 in FIG. Since it is usually impossible to select the low speed side by the speed mode selection means immediately after the high speed mode is selected by the speed mode selection means and the operation lever 10 is wound up, the controller 50 determines NO in step S9. Do.

Next, in step S10 of FIG. 5, the controller 50 determines whether the control lever 10 is neutral. In step S10, when the control lever 10 is neutral, the control process transitions to step S13. On the other hand, in step S10, when the control lever 10 is not neutral (in the case of non-neutral), the control processing shifts to step S7. In the case immediately after the start of the winding operation, since the operation lever 10 is non-neutral, the controller 50 determines NO in step S10. Thereafter, the control flow from step S7 to step S10 loops continuously. That is, while the control process loops from step S7 to step S10, the winding operation is continued while the high and low speed hydraulic motor 21 is in the high speed mode.

As described above, in the initial stage of ground cutting, the calculated lifting load and wire rope tension start from zero and gradually increase regardless of the actual lifting load. Therefore, in the winch system of the mobile crane according to the present invention, if the high speed mode is selected by the speed mode selection means, the hoisting load calculation value and the wire rope tension calculation value are low at high speed at the ground cutting initial stage. Improves the workability of the crane.

In the state where the ground removal is completed (see FIG. 7), when the controller 50 determines NO in step S7 and step S8 of FIG. 5, a loop of control flow from step S7 to step S10 continues. . That is, in this case, the high and low speed hydraulic motor 21 is operated in the high speed mode until the operation lever is returned to neutral (step S10).

On the other hand, when the controller 50 determines YES in step S7 or step S8 of FIG. 5 in the middle of ground cutting, the low speed side switching signal is output to the electromagnetic switching valve 33 in step S11 of FIG.

In this case, the low speed side switching signal is output from the drive control unit 64 shown in FIG. 3 to the electromagnetic switching valve 33. As shown in FIG. 2, the electromagnetic switching valve 33 switches to the shutoff side, the pilot pressure of the oil passage 34 acting on the pilot switching valve 30 returns to the tank, and the pilot switching valve 30 switches to the shutoff side. Further, the pressure oil applied to the control cylinder 24 returns to the tank via the oil passage 31 and the pilot switching valve 30. Then, the high / low speed motor 21 constantly urged to the low speed side returns to the low speed side.

At this time, since the drive signal output to the winding proportional solenoid valve 35 shown in step S3 of FIG. 4 is continued, the winding in the low speed mode is performed. When the operation in the low speed mode shown in FIG. 6 is started, in step S12, the controller 50 determines whether the control lever 10 is neutral. If it is determined in step S12 that the control lever 10 is not neutral, the control flow loops in steps S11 and S12 of FIG. That is, the operation in the low speed mode of the high and low speed hydraulic motor 21 continues.

When the operation lever 10 is returned to the neutral state in step S10 during the operation in the high speed mode in which steps S7 to S10 shown in FIG. 5 are looped ("YES" in step S10), the control process transitions to step S13. Do. In step S13, the low speed side switching signal is output to the electromagnetic switching valve 33 (see FIG. 2). Further, in step S14, the drive signal output to the solenoid proportional valve 35 on the winding side is stopped. That is, the high / low speed hydraulic motor 21 returns to the low speed side, the pilot switching valve 32 switches to the neutral position, and the pressure oil from the hydraulic pump 40 is not supplied to the high / low speed hydraulic motor 21. Then, the high and low speed hydraulic motor 21 is stopped.

Similarly, during operation in the low speed mode shown in FIG. 6, when the control lever 10 is neutral in step S12 ("YES" in step S12), in step S14 in FIG. The drive signal output is stopped, and the high and low speed hydraulic motor 21 operating in the low speed mode is stopped.

(In case of ground winding in low speed mode selection)
An example in the case of winding up in low speed mode from the state (refer FIG. 1) in which the suspended load 18 earth | grounded on the ground 20 is demonstrated. First, in step S1 of FIG. 4, the controller 50 determines whether the speed mode selection means 51 (see FIG. 3) is selected to the high speed side. In the case of this example, the controller 50 determines NO in step S1.

Next, in step S15 in FIG. 4, the controller 50 determines whether the control lever 10 is neutral. If the control lever 10 is neutral at step S15 ("YES" at step S15), the control processing returns to step S1. On the other hand, when the control lever 10 is non-neutral (in the case of the present example, the winding side) in step S15 ("NO" in step S15), a drive signal is output to the winding proportional solenoid valve 35.

Next, a pilot pressure acts from the solenoid proportional valve 35 shown in FIG. 2 via the oil passage 37, and the pilot switching valve 32 is switched. Then, pressure oil is sent from the hydraulic pump 40 to the oil passage 25 on the winding side via the oil passage 42. As a result, the high and low speed motor 21 drives the winch drum 22 to the winding side in the low speed mode. Thereafter, the flow shown in FIG. 6 is continued to continue the operation in the low speed mode.

(In the case of lifting from the suspended state in high-speed mode selection)
An example will be described in the case where the suspended load 18 is hoisted in a high speed mode from a suspended state (see FIG. 7) separated from the ground 20.

First, in step S1 of FIG. 4, the controller 50 determines whether the speed mode selection means 51 is selected to the high speed side. In the case of this example, the controller 50 determines YES in step S1.

Next, in step S2 of FIG. 4, the controller 50 determines whether the control lever 10 is neutral. When the control lever 10 is non-neutral (roll-up side or roll-down side) in step S2 of FIG. 4 (“NO” in step S2), a drive signal is output to the roll-up electromagnetic proportional valve 35.

Then, the pilot pressure acts from the solenoid proportional valve 35 or the solenoid proportional valve 36 shown in FIG. 2 via the oil passage 37 or the oil passage 38, and the pilot switching valve 32 is switched. Then, pressure oil is sent from the hydraulic pump 40 via the oil passage 42 to the oil passage 25 on the winding side or the oil passage 26 on the winding side. Thus, the operating pressure of the high and low speed hydraulic motor 21 is generated in the oil passage 25 on the winding side or the oil passage 26 on the winding side. In addition, when the control lever 10 is neutral in step S2 ("YES" in step S2), the flow continues until the control lever 10 becomes non-neutral.

Next, in step S4 of FIG. 4, the controller 50 determines whether the suspension load calculation value is smaller than the suspension load threshold. In the case of this example, since the suspended load 18 is suspended, there is no elongation of the wire rope 14 and no occurrence of distortion of the telescopic boom 12, so the calculated suspended load value calculates the true suspended load value almost simultaneously when the winch system 1 is activated. Be done. Therefore, in step S4, the true suspension load value calculation value is compared with the suspension load threshold value. If the true suspension load value operation value is not smaller than the suspension load threshold in step S4 ("NO" in step S4), the control process transitions to step S11 in FIG. Then, in step S11, the low speed side switching signal is output to the electromagnetic switching valve 33. As a result, the winch 11 operates in the low speed mode.

On the other hand, when the true suspension load value operation value is smaller than the suspension load threshold in step S4 ("YES" in step S4), the control process transitions to step S5. In step S5, the controller 50 determines whether the calculated wire rope tension value is smaller than the wire rope tension threshold value. In the case of this example, since the load 18 is suspended, the wire rope tension does not occur and the stretchable boom 12 does not occur, so the wire rope tension calculation value is a true wire rope tension calculation value almost simultaneously with the activation of the winch system 1 Is calculated. Therefore, in step S5, the true wire rope tension calculation value is compared with the wire rope tension threshold value. When the calculated wire rope tension value is not smaller than the wire rope tension threshold in step S5 ("NO" in step S4), the control process transitions to step S11 of FIG. 6, and the low speed side switching signal is output to the electromagnetic switching valve 33 And the winch 11 operates in the low speed mode.

At this point, the speed mode selection means 51 is selected to the high speed side (condition 1), the operation lever 10 is operated from neutral to non-neutral (condition 2), and the suspension load calculated value is smaller than the suspension load threshold (condition 3) And the wire rope tension calculation value is smaller than the wire rope tension threshold (condition 4). It is determined whether all the four conditions are satisfied. As described above, in the case of lifting from the suspended state in the high speed mode selection, the determination of the operating condition that allows the high speed mode is completed in a very short time as compared to the winding from the ground cutting. Then, the operation in the high speed mode or the operation in the low speed mode continues. The content of the control flow during the operation in the high speed mode described in FIG. 5 is the same as that in the case of starting from the ground cutting, so the detailed description thereof will be omitted.

(In the case of lifting from the suspended state in the low speed mode selection)
An example will be described in the case where the suspended load 18 is hoisted in a low speed mode from a suspended state (refer to FIG. 7) separated from the ground 20. First, in step S1 of FIG. 4, the controller 50 determines whether or not the speed mode selection means 51 is selected to the high speed side. In the case of this example, the controller 50 determines NO in step S1.

Next, in step S15 in FIG. 4, the controller 50 determines whether the control lever 10 is neutral. When the control lever 10 is neutral at step S15 ("YES" at step S15), the control processing shifts to step S1. On the other hand, if the control lever 10 is non-neutral (roll-up side or roll-down side) in step S15 ("NO" in step S15), roll-up electromagnetic proportional valve 35 or roll-down electromagnetic proportional valve 36 in step S16. Drive signal is output. From this point onward, since the flow shown in FIG. 6 is continued to continue the operation in the low speed mode, the detailed description will be omitted.

<Supplementary Note>
The winch system provided in the crane according to the present invention may have the following configuration.

<First example of winch system>
Specifically, the winch system includes a winch driven by a high / low speed hydraulic motor, an operation lever for operating the winch, and a speed mode selection means capable of selecting the high / low speed hydraulic motor in high speed mode or low speed mode. Load detection means for detecting the length of telescopic boom, undulation angle, pressure of the relief cylinder, Wire rope hook number input means for inputting the number of wire rope hooks, operation lever, speed mode selection means, for load And a controller for receiving a signal from the wire rope multiplication number input means and outputting a drive signal to the winch.
The high and low speed hydraulic motor is provided with a control cylinder that controls the motor displacement in a large and small manner, and a high and low speed switching valve that switches the motor operating pressure to and from the control cylinder.
The motor displacement is always biased to the large displacement side, and when the high / low speed switching valve is switched to the high speed side, the motor operating pressure is communicated to the control cylinder to switch the motor displacement to the small displacement side.
The controller calculates a suspension load, a suspension load calculation unit, a wire rope tension calculation unit for computing a wire rope tension, a suspension load comparison unit for comparing a suspension load calculation value and a suspension load threshold, and a wire rope tension calculation value The switching signal of the high / low speed switching valve is output based on the signals from the wire rope tension comparison unit that compares with the wire rope tension threshold, the operation lever, the speed mode selection means, the suspension load comparison unit, and the wire rope tension comparison unit. And a drive control unit.
In the drive control unit, the speed mode selection means is selected to the high speed side, the control lever is operated from neutral to non-neutral, the suspension load calculated value is smaller than the suspension load threshold, and the wire rope tension calculated value is greater than the wire rope tension threshold And outputs a signal for switching the high / low speed switching valve to the high speed side when all the four conditions of “small” are satisfied.

According to such a winch system, since the hoisting load calculation value and the wire rope tension calculation value can be wound at high speed in the early stage of the ground cutting, the crane workability can be improved.

Also, when the condition that the suspension load is smaller than the suspension load threshold and the condition that the wire rope tension is smaller than the wire rope tension threshold are simultaneously satisfied, the high / low speed switching valve is switched to the high speed side. For this reason, even when there is an erroneous wire rope hook number input, switching to the high speed side under the condition that an excessive rope tension acts is prevented.

Second Example of Winch System
In addition, when the above-mentioned winch system is implemented, preferably, in the state where the high / low speed switching valve is switched to the high speed side, the suspension load comparing unit does not have the suspension load calculation value not smaller than the suspension load threshold. If the wire rope tension comparison unit continuously detects that the calculated wire rope tension value is not smaller than the wire rope tension threshold for a predetermined time, the drive control unit continuously detects the predetermined time, or It outputs a signal to switch the high / low speed switching valve to the low speed side.

The above-described winch system can prevent the operating pressure of the high and low speed hydraulic motor from exceeding the allowable range. The reason for this is that when the suspension load is not continuously smaller than the suspension load threshold for a predetermined time, or the wire rope tension comparator does not calculate the wire rope tension calculated value as the wire rope tension threshold. This is because the high and low speed hydraulic motor is switched to the low speed side (large capacity side) even when the speed mode selection means is switched to the high speed side when detection is continuously performed for a predetermined time.

In addition, since it was determined that the condition which is not smaller than the threshold is continued for a predetermined time, frequent high-low speed switching that occurs due to apparent load fluctuation accompanying the vibration of the telescopic boom or wire rope is prevented, and stable control Is done.

<Third example of winch system>
Moreover, when implementing the above-mentioned winch system, it is preferable that a drive control part continues the output of the signal which switches a high-low speed switching valve to the low speed side until a control lever becomes neutral.

According to such a winch system, it is possible to prevent the mode from being switched due to the fluctuation of the detection value even under the condition that the detection suspension load or the detection wire rope tension is near the threshold value. The reason is that the low speed mode is selected until the operation lever becomes neutral when the high / low speed hydraulic motor is switched to the low speed side (large capacity side) while operating in the high speed mode while the speed mode selection means is switched to the high speed side. To maintain

<The 4th example of a winch system>
In the case where the above-mentioned winch system is implemented, the drive control unit performs high-low speed switching when the speed mode selection means is switched to the low-speed side while the high-low speed switching valve is switched to the high speed side. It is preferable to output a signal for switching the valve to the low speed side.

According to such a winch system, even if the speed mode selection means is switched to the high speed side and the vehicle is operating in the high speed mode, it is possible to switch to the low speed mode by the intention of the operator.

The disclosures of the specification, drawings and abstract contained in the Japanese application of Japanese Patent Application No. 2017-241947 filed on Dec. 18, 2017 are all incorporated herein by reference.

DESCRIPTION OF SYMBOLS 1 winch system 10 control lever 11 winch 12 telescopic boom 13 undulating cylinder 14 wire rope 15 tip 16 hook 18 suspension load 2 rough terrain crane 20 ground 21 high speed hydraulic motor 22 winch drum 23 reduction gear 24 control cylinder 25 oil on winding side Path 26 Oil path on the lower side 27 Counter balance valve 28 Shuttle valve 3

Vehicle part

30, 32

Pilot switching valve

31, 34 Oil path 33

Solenoid switching valve

35, 36 Solenoid

proportional valve

37, 38 Oil path 4 Swirl part 40 Pump 41

Tank

42, 43 Oil passage 5 Outrigger 50 Controller 51 Speed mode selection means 52 Load detection means 53 Wire rope hook number input means 54 Boom length detector 55 Angle detector 56 Pressure detector 6 Frame 60 Hanging load calculator 61 Wire rope Tension calculation unit 62 Suspension load comparison unit 63 Wire rope tension comparison unit 64 Drive control unit 7 Operator's cab

Claims

Operation unit,
A winch device that operates in either the high speed mode or the low speed mode based on the operation of the operation unit, and takes up and unwinds a wire rope to which a hook is fixed;
A selection unit for the operator to select one of the high speed mode and the low speed mode;
A load calculation unit that calculates a hanging load;
A tension calculation unit that calculates tension of the wire rope;
A control unit that controls the operation of the winch device;
In the control unit, the mode selected by the selection unit is the high-speed mode, and the operation unit is operated from the neutral state to the non-neutral state, and the suspension load is smaller than the load threshold, and Controlling the winch device to operate in the high speed mode if the tension is less than a tension threshold,
crane.
The winch device comprises a high and low speed hydraulic motor having a high and low speed switching valve and a control cylinder,
The high / low speed switching valve is a first state in which hydraulic oil is supplied from the high / low speed switching valve to the control cylinder under the control of the control unit, and supply of hydraulic oil from the high / low speed switching valve to the control cylinder It is possible to switch between the second state that shuts off the
In the second state, the motor displacement of the high / low speed hydraulic motor is a large displacement side corresponding to the low speed mode, and in the first state, the motor displacement is a small displacement side corresponding to the high speed mode. The crane of item 1.
In the state where the winch device is operated in the high speed mode, the control unit continues the state where the suspension load is above the suspension load threshold for a predetermined time, or the tension is above the tension threshold The crane according to claim 1, wherein switching control is performed to switch the operation mode from the high speed mode to the low speed mode when the state continues for a predetermined time.
The crane according to claim 3, wherein the control unit maintains the operation mode in the low speed mode until the operation lever becomes neutral after the switching control.
The control unit controls the winch device to operate in the low speed mode when the low speed mode is selected by the selection unit while the operation mode is the high speed mode. Description crane.